The term zwitterion has been defined as a complex ion that is both negatively and positively charged.
Adhesive compositions commonly contain an adhesive polymer together with a tackifier or plasticizer. The adhesive polymer provides cohesion and the tackifier or plasticizer increases tack. Typically, tackifiers increase the glass transition temperature of polymers, whereas plasticizers lower the glass transition temperature of the polymers. However, both tackifiers and plasticizers improve the tack of adhesive polymers.
PSAs are used in a wide range of applications such as masking tapes, mending and sealing tapes, hair care tapes, electrical tapes, packaging tapes and labels. There is always a need to find new tackifiers and plasticizers for the compositions to improve their properties.
Further, applicant's copending application U.S. Ser. No. 09/042,980 entitled "Adhesive Compositions And Adhesive Tapes Comprising Zwitterionic Copolymers, And Novel Zwitterionic Copolymers". hereby incorporated by reference) discloses adhesive copolymers having a zwitterionic monomer component. Conventional tackifiers and plasticizers are not entirely satisfactory with these copolymers. It would be desirable to find tackifiers and plasticizers which would be more effective for use with such copolymers.
Conventional tackifiers include polysaccharide gums, rosins, rosin derivatives, alkyl/aryl hydrocarbon resins and derivatives, and petroleum-aliphatic resins. Conventional plasticizers include polyoxyethylene alkylphenyl ether phosphates, polyoxyethylenealkyl ether phosphates, polyethyleneglycolmonophenyl ethers, octylphenoxypoly (ethyleneoxy) ethanols and nonylphenoxypoly (ethyleneoxy) ethanols.